title: Diffusion tensor imaging of the superior cerebellar peduncle identifies patients with posterior fossa syndrome.
abstract: BACKGROUND
  Posterior fossa tumors are the most common brain tumor of children. Aggressive resection correlates with long-term survival. A high incidence of posterior fossa syndrome (PFS), impairing the quality of life in many survivors, has been attributed to damage to bilateral dentate nucleus or to cerebellar output pathways. Using diffusion tensor imaging (DTI), we examined the involvement of the dentothalamic tracts, specifically the superior cerebellar peduncle (SCP), in patients with posterior fossa tumors and the association with PFS.
  
  
  METHODS
  DTI studies were performed postoperatively in patients with midline (n = 12), lateral cerebellar tumors (n = 4), and controls. The location and visibility of the SCP were determined. The postoperative course was recorded, especially with regard to PFS, cranial nerve deficits, and oculomotor function.
  
  
  RESULTS
  The SCP travels immediately adjacent to the lateral wall of the fourth ventricle and just medial to the middle cerebellar peduncle. Patients with midline tumors that still had observable SCP did not develop posterior fossa syndrome (N = 7). SCPs were absent, on either preoperative (N = 1, no postoperative study available) or postoperative studies (N = 4), in the five patients who developed PFS. Oculomotor deficits of tracking were observed in patients independent of PFS or SCP involvement.
  
  
  CONCLUSIONS
  PFS can occur with bilateral injury to the outflow from dentate nuclei. In children with PFS, this may occur due to bilateral injury to the superior cerebellar peduncle. These tracts sit immediately adjacent to the wall of the ventricle and are highly vulnerable when an aggressive resection for these tumors is performed.
authors.affiliation: Neurosurgery, Seattle Children's Hospital, Seattle, WA, USA, jeff.ojemann@seattlechildrens.org.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Ojemann
authors.forename: Savannah C
authors.initials: SC
authors.lastname: Partridge
authors.forename: Andrew V
authors.initials: AV
authors.lastname: Poliakov
authors.forename: Toba N
authors.initials: TN
authors.lastname: Niazi
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Shaw
authors.forename: Gisele E
authors.initials: GE
authors.lastname: Ishak
authors.forename: Amy
authors.initials: A
authors.lastname: Lee
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Browd
authors.forename: J Russell
authors.initials: JR
authors.lastname: Geyer
authors.forename: Richard G
authors.initials: RG
authors.lastname: Ellenbogen
mesh_terms: D000293:Adolescent; D000328:Adult; D002528:Cerebellar Neoplasms / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D015192:Infratentorial Neoplasms / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D008297:Male; D009155:Mutism; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D013577:Syndrome; D016896:Treatment Outcome; D055815:Young Adult